On Fri, Nov 12, 2010 at 7:10 PM, Jason Grout <jason-s...@creativetrax.com> wrote: > On 11/12/10 8:48 PM, Jason Grout wrote: >> >> On 11/12/10 6:22 PM, Maxim wrote: >>> >>> I get very high memory usage when I do something like: >>> sage: get_memory_usage() >>> -> 809.9453125 >>> sage: A=vector(range(0,10000))/1 >>> sage: get_memory_usage() >>> -> 5393.2734375 >>> >>> Which is a whooping 4.5GB+ of memory to hold a 10000 float vector... >>> >>> I would have thought more of something along the lines of 24bytes/ >>> float * 10000 floats + some overhead for the vector object ~= 240KB. >>> > > > > The problem seems to stem from the lines > > cdef Element x = X.an_element() > cdef Element y = Y.an_element() > > inside of the detect_element_action function in coerce_actions.pyx. Notice: > > sage: v=vector(range(10000)) > sage: get_memory_usage() > 206.84765625 > sage: w=v.parent().an_element() > sage: get_memory_usage() > 3321.14453125 > > I'm not sure why the coercion system *has* to construct an element, > especially if such an element could potentially be expensive to compute and > store.
It only has to construct an element if it can't figure out what to do after consulting the Parents themselves. > And then there's the matter you talk about; why is an element so big? The example above is quite strange. No idea why it should be so big. (Note that these are are arbitrary precision integers, so the relative overhead for small ones is still quite large). As for the original example, sage: type(vector(RR, range(100))) <type 'sage.modules.free_module_element.FreeModuleElement_generic_dense'> Which means that each element is a full Python RealNumber, quite a bit more than a double. Still doesn't explain the memory usage. For almost any kind of linear algebra, you're better off using RDF, or even numpy directly. There's something really fishy going on, as sage: get_memory_usage() 222.671875 sage: A=vector(range(0,1000)) sage: get_memory_usage() 222.671875 sage: A=vector(range(0,1000))/1 sage: get_memory_usage() # barely any more... 253.67578125 sage: A=vector(range(0,10000))/1 # eats up *tons* of memory, swapping like crazy. - Robert -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
